Modern aircraft have a need to provide radio communication over a variety of frequency ranges and communication modes. For example, radio communication may be in the UHF band or the L band. In order to communicate effectively, the aircraft must include multiple antennas placed in various locations on the aircraft. Typically, the aircraft may include antennas mounted behind the radio transparent skin of the aircraft, and/or exterior blade antennas mounted on the skin of the aircraft. Blade antennas are small fins protruding from the skin of the aircraft that are used as the radiating element. The blade antennas are electrically matched through impedance matching networks to transmitting and receiving equipment.
Blade antennas are aerodynamically inefficient because they protrude from the skin of the aircraft. Typically, multiple blade antennas are used on the aircraft to accommodate multiple communications bands (i.e., UHF, VHF/FM, VHF/AM). Blade antennas are constructed to withstand the forces subjected to the antenna. However blade antennas are still susceptible to impact damage. In addition, blade antennas do not add any structural strength to the aircraft, and may interfere with the aerodynamic efficiency of the aircraft.
Antenna radiating elements may also be embedded within the skin of the aircraft. Such radiating elements provide an antenna structure for the aircraft that is structurally integrated within the skin thereof. However, these embedded antenna structures are typically difficult to manufacture and install. Additionally, embedded antenna structures may not exhibit ideal gain characteristics.
A significant problem facing some aircraft is a lack of space on the top and bottom surfaces of the fuselage to mount antennas. If it were possible to relocate existing blade antennas, additional surface area on the aircraft fuselage would be available for new antennas. In addition, cosite interference to existing blade antennas could be reduced.
The present invention addresses the above-mentioned deficiencies in prior aircraft antenna design by providing an antenna assembly that fits into existing openings in an aircraft at portions of the fuselage not previously used for mounting antennas.